1. Field of the Invention
The present invention relates to a polyphenylene ether resin composition. In particular, the present invention relates to a resin composition comprising a polyphenylene ether (hereinafter often referred to as "PPE") having a stabilized terminal structure.
2. Description of the Related Art
PPE is one of useful resins. In particular, a polymer alloy of PPE and polystyrene or polyamide is excellent in thermal properties, mechanical properties, electrical properties and so on, and, in these years, increasingly used as a molding material in the automobile, electric and electronic fields and so on.
Hitherto, in a widely known process, PPE is prepared by oxidation polymerizing a nucleus substituted phenol in the presence of a catalyst comprising a complex of manganese, copper, cobalt and the like (cf. Japanese Patent Publication No. 23291/1993 and U.S. Pat. No. 4,092,294).
Macromolecules, 1990, 23, 1318-1329 describes that PPE which is obtained by the polymerization in the presence of a secondary monoamine has a terminal structure of the formula (3): ##STR2## wherein R.sub.1 to R.sub.5 represent independently each other a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.20 alkyl group, a substituted C.sub.1 -C.sub.20 alkyl group, a C.sub.2 -C.sub.20 alkenyl group, a substituted C.sub.2 -C.sub.20 alkenyl group, a C.sub.2 -C.sub.20 alkynyl group, a substituted C.sub.2 -C.sub.20 alkynyl group, a C.sub.6 -C.sub.20 aryl group or a substituted C.sub.6 -C.sub.20 aryl group, and R.sub.12 and R.sub.13 represent independently each other a C.sub.1 -C.sub.20 alkyl group or a substituted C.sub.1 -C.sub.20 alkyl group.
However, PPE having this terminal structure (3) has drawbacks such as coloring and increase of a viscosity in a heating step such as granulation or molding.
Japanese Patent KOKAI Publication No. 253725/1992 discloses that PPE which is obtained by the polymerization in the presence of a primary monoamine has a terminal structure of the formula (4): ##STR3## wherein R.sub.14 is a lower alkyl group.
However, U.S. Pat. Nos. 4,092,294 and 4,477,651 which the invention of the above Japanese KOKAI publication is based on disclose only an alkylamine as the primary monoamine. Further, U.S. Pat. No. 4,092,294 describes that PPE which is obtained by the polymerization in the absence of the secondary monoamine is heavily colored, and a mixture of such PPE and a styrene resin has deteriorated thermal stability and mechanical properties.
Japanese Patent KOKAI Publication No. 239323/1993 discloses a modified polyphenylene ether prepared by a reaction of PPE and a primary amine. However, this publication describes only an alkylamine as the primary amine, and the modified polyphenylene ether has an insufficient effect to suppress the increase of coloration during heating.
Japanese Patent Publication No. 69946/1991 discloses a resin composition comprising PPE and a primary aromatic amine, which composition suffers from only small decrease of mechanical properties in a high temperature processing, and provides a molded article having good surface gloss. However, the primary aromatic amine comprises an aromatic ring and an amino group which directly bond each other, and cannot suppress an increasing degree of coloration in the heating step such as granulation and molding.
Japanese Patent Publication No. 25525/1994 discloses a resin composition comprising PPE and 0.01 to 5 parts by weight of a primary amine per 100 parts by weight of PPE, which composition has an improved resistance to discoloration by light, and exemplifies a composition comprising 100 parts by weight of PPE and 5 parts by weight of benzylamine as the primary amine. However, the increase of an amount of benzylamine leads to some problems such as decrease of mechanical properties of a molded article, inclusion of bubbles in the molded article, and generation of amine odor during molding. This Japanese Patent Publication does not refer to the increase of coloration in the heating step such as granulation and molding, or suppression of the viscosity increase.